An iron type golf club head, as well known, includes a face part, which has a plate-shape face surface, and a hosel part, which is connected to the heel side of the face part. A shaft insertion hole is provided at the hosel part. A shaft is inserted into the shaft insertion hole and fixed with adhesive agent.
Patent Doc. 1 discloses a golf club head in which a hitting surface plate is glued to the hitting surface spot of the head body with a shock absorbing layer.
Patent Doc. 2 discloses a head in which a middle layer made of buffer material intervening at the face surface side of the head body.
As for wood type golf club heads for drivers or fairway woods, heads made of metal in a hollow shape are well known. In general, a wood type golf club head in a hollow shape includes a face part for hitting a ball, a crown part comprising the upper surface part, a sole part comprising a sole part of the golf club head, a side part comprising surrounding parts at the toe side, at the back side and at the heel side of the golf club head, a hosel part. As for the metal comprising the hollow shape golf club head, aluminum alloy, stainless or titanium alloy are used. In case of a driver, titanium alloy recently has been widely used.
Patent Doc. 3 describes a golf club head having an elastic body layer arranged at the face part of the head body and a fiber reinforced resin layer covering the surface of the elastic body.